Watch Over Me — Gail R. Delaney

Ten years ago, Donovan Greer lost everything. Now, he wants to feel nothing and exists only for his work. Until he is assigned to protect Olivia Weston -- The Sweetheart of Broadway -- from a sociopath dubbed The Broadway Killer.
Olivia's life and career has been micromanaged since she was young. Donovan puts decision into her hands and treats her like a woman, not a commodity. He makes her fall in love with him, whether it was his intention or not.
Her beauty and grace would be easy enough for Donovan to ignore - if Olivia didn't want him as much as he denies he wants her. He knows it's not smart, and tries every excuse he can to dissuade her - including their fourteen year age difference. It's been a long time since he let his heart feel anything, but once it does, it's impossible to ignore.
When danger stalks the shadows, and her life is in his hands, he wonders if he is capable of loving her and protecting her. He failed once to protect the woman who loved him. He can't fail again.